As a conventional fuel treatment device, there has been known one which has a cylindrical shape on the whole, includes on its center a heater having a burner, and includes around the heater a reformer filled with a reforming catalyst, a transformer filled with a carbon monoxide (CO) transforming catalyst, and a CO remover filled with a carbon monoxide (CO) removal catalyst, which are arranged in parallel in the axial direction (see, Patent Literature 1). In this fuel treatment device, a raw material and reforming water are supplied to a gas flow channel serving as an evaporator provided around the heater, and the raw material and generated vapor are supplied to the reformer. Further, a hydrogen-containing gas delivered from the reformer is sequentially supplied to the transformer, provided at the outer circumference of the gas flow channel, and the CO remover, whereby a reformed gas is produced.
FIG. 1 is a longitudinal cross-sectional view showing a structure of the fuel treatment device described in Patent Literature 1.
Fuel treatment device 1 shown in FIG. 1 has a cylindrical shape on the whole and is heat-insulated by heat insulating material 1a covering the outer surface of fuel treatment device 1. Fuel treatment device 1 has on its center heater 5 having combustion cylinder 3 arranged with burner 2 and exhaust gas passage 4 at the outer circumference of combustion cylinder 3. Outlet 4a of exhaust gas passage 4 is opened to outside. First gas flow channel 6 serving as an evaporator is provided at an outlet side portion of the outer circumference of exhaust gas passage 4 of heater 5. Reformer 8 filled with reforming catalyst 7 is provided at the outer circumference of exhaust gas passage 4 on the side to which a high-temperature exhaust gas flows from combustion cylinder 3. Reformer 8 has at its outer circumference second gas flow channel 9 for circulating a hydrogen-containing gas, delivered from reformer 8, toward the side of the outer circumference of first gas flow channel 6. Transformer 11 filled with CO transforming catalyst 10 is provided at the outer circumference of the first gas flow channel 6 on the side of reformer 8. CO remover 14 filled with CO removal catalyst 13 is provided at the outer circumference of first gas flow channel 6 on the side farther from reformer 8 and connected to third gas flow channel 12 provided more inwardly than CO remover 14 in the radial direction.
A raw material is supplied from inlet 6a of first gas flow channel 6 to be mixed with reforming water in inlet 6a. The reforming water is supplied through heating coil 15 wound around the outer circumference of transformer 11 and CO remover 14. The raw material and the reforming water are heated while passing through first gas flow channel 6 serving as an evaporator. The high-temperature raw material and vapor are supplied to reformer 8, and the raw material is steam-reformed by the action of reforming catalyst 7 to be a hydrogen-rich hydrogen-containing gas.
The hydrogen-containing gas delivered from reformer 8 is supplied to transformer 11 through second gas flow channel 9, and carbon monoxide (CO) contained in the hydrogen-containing gas is reduced by the action of CO transforming catalyst 10. The hydrogen-containing gas delivered from transformer 11 is mixed with air introduced from air inlet 16a in air mixing space 16 provided between transformer 11 and third gas flow channel 12. The hydrogen-containing gas mixed with the air is supplied to CO remover 14 through third gas flow channel 12, CO is then removed by the action of CO removal catalyst 13, and the hydrogen-containing gas is delivered from outlet 17.
The fuel treatment device shown in FIG. 1 has third gas flow channel 12 interposed between CO remover 14 and high-temperature first gas flow channel 6. Therefore, while the temperature at the downstream portion of transformer 11 can be maintained at a temperature suitable for reaction (for example, 200° C.), the entrance temperature of CO remover 14 can be maintained at a temperature of a level short of excessively promoting oxidation reaction (for example, 150° C.). Namely, it is advantageous that transformer 11 and CO remover 14 can be maintained at a suitable temperature.
Patent Literature 2 discloses a fuel reformer filled with a granular reforming catalyst. Specifically, a plurality of partition walls are provided at an interval along a direction of circulating a raw fuel, and the granular reforming catalyst is loaded on the disposed partition walls. The partition walls have through-holes, and a gap is provided between the partition wall and a cylindrical body of the fuel reformer.
In addition, there is also an attempt to expressly indicating a reusable member to promote recycle (see, Patent Literature 3).    Patent Literature 1: Japanese Patent Application Laid-Open No. 2007-331985    Patent Literature 2: Japanese Patent Application Laid-Open No. 8-208202    Patent Literature 3: Japanese Patent Application Laid-Open No. 11-26896